And et cetera: Et cetera means “and the other things.” The extra and is not needed.

2-year anniversary: Anniversary’s Latin roots translate to “returning yearly.” The year part is built right in. This also means you should never use anniversary when referring to months (or weeks or days, weirdo).

Many arise from initialisms, abbreviations where each individual letter is pronounced, and acronyms, abbreviations where the whole thing is pronounced as a word: